Ever had a big-yet-broad investment idea? Now you can bet on it. Online brokerage start-up Motif Investing offers stock bundles based on thematic ideas such as "Clean Tech" or "Online Gaming World," and it's gaining interest from Wall Street's biggest players.

Think of the investments as "crowdsource-able, customizable, no-fee ETFs," Motif's co-founder and CEO Hardeep Walia told CNBC on Friday. Other investment themes—or motifs as the company calls them—fall under the names: "Chinese Solar" or "Biotech Breakthroughs."

Some of the themes provide investors with enviable returns, according to Motif. The "Online Gaming" motif, for example, has a year-to-date return of 12.4 percent—good for several times the year-to-date returns of the S&P 500. Wall Street's biggest names have taken notice, with JPMorgan Chase investing $35 million into the nascent company.

The brokerage charges $9.95 for a motif made up of a maximum 30 stocks or ETFs. Investors can compile their own motif, or join an already created bundle.

Walia told CNBC that the start-up wants to expand internationally and push its scope past retail investors. The brokerage also wants to offer its investment motifs to financial advisors, he said.

"An idea can be anything," Walia said on "Squawk on the Street." "It doesn't have to be a hot new trend like robotics, it can be a trading strategy or it can be an Ivy League endowment model. We make it supereasy for retail investors and now advisors to take advantage of our platform."

The brokerage first came up with about 120 motifs. In six months, its users have created about 35,000, Walia said. There's an Obamacare motif—and a "Repeal Obamacare" motif. The former has trounced the latter in 52-week returns so far.

Other winning themes include "Tablet Takeover" and "Mobile Internet." The "Online Gaming" motif is made up of stocks such asElectronic Arts, Activision Blizzard and NetEase. Motifs such as "Cyber Security" have dropped as much as 18 percent this year, withFireEye dragging down the category.

Walia said Motif's novel approach to investing also serves as a measure of public sentiment.

"We now have a very good sentiment of what people really think," Walia said. "Not what they tell their pollsters, but where they put their money. We can tell you what rich people, what poor people, young people or old people think about trends like Obamacare just by where they are putting their money."